The 13th International Conference on Microbial Genomes will continue the tradition of bringing investigators from biology, technology and computer sciences together to discuss the most recent advances in microbial genomics. This year's addition of the series will continue to incorporate frontier areas including new microbial communities, metagenomics and "synthetic biology" including the modeling and building of genetic circuits and metabolic pathways and conceivably the synthesis of completely artificial genomes. We will also emphasize a new focus, the field of structural proteomics. The combination of topics presented by leaders in the field, will offer attendees both the opportunity to build on existing genomic projects or initiate new research utilizing the latest technology. As with past meetings, we expect participants from a wide range of disciplines, including those from both academic and industrial institutions. In addition, this conference will provide fellowship awards to support graduate students in order to train the next generation of genomic experts. The conference will consist of seven sessions: (1) Host-microorganism interactions; (2) Community biology/metagenomics and pathogenesis; (3) Synthetic biology/syngenomics; (4) Computer modeling and systems biology; (5) Pathway engineering; (6) Structural genomics; and (7) New horizons. There will also be an afternoon poster session on Monday, Tuesday and Wednesday offering the opportunity for all the participants to present their work. The conference will be held at the Lowell Center on the University of Wisconsin-Madison campus from September 11 to 15, 2005. Frederick R. Blattner (UW-Madison), who has been an integral part of the Conference since its inception, will chair this year's meeting. The organizing committee consists of Jeffrey H. Miller (University of California at Los Angeles), Monica Riley (Marine Biological Laboratory), Elisabeth Raleigh (New England Biolabs, Inc.), George Weinstock (Baylor College of Medicine), Jizhong Zhou (Oak Ridge National Laboratory) and Tim Durfee (UW-Madison).